There are many instances where it would be convenient to adjust the tint (i.e., the “darkness”) of eyewear. When driving, for example, the amount of sun glare may change on a moment's notice, particularly when changing directions. The ability for a wearer to adjust the tint of his/her sunglasses would be useful. Various other types of eyewear—traditional eye glasses, goggles, safety glasses, and the like—could benefit from this ability of allowing the wearer to adjust the tint quality.
For years, there have been sunglasses that have “self-adjusted” their degree of tint as a function of the ambient light conditions. That is, the glasses would “lighten” when an individual would go indoors, and would then darken when going back outside. While useful in many situations, various versions of these self-darkening lenses have been only moderately successful. At times, the material used to form the lenses does not allow for a sufficient lightening effect to be obtained. Moreover, it generally takes a few minutes for the lenses to change their tint. When driving, this slow reaction time is unacceptable. Additionally, the wearer cannot control the amount of tint, or the circumstances under which the lenses will become darker or lighter; that is, the wearer is at the mercy of the photochromic properties of the lens material and cannot provide any type of adjustment him/herself.
There are various arrangements in the prior art directed to providing adjustment of eyewear tint that address the concerns associated with using lenses that automatically (via a chemical process) change tint. One exemplary adjusting arrangement is disclosed in U.S. Pat. No. 5,320,552, issued to P. Baran et al. on May 11, 1993. The Baran et al. configuration, described as a pair of “variable density sunglasses”, uses two separate elements of polarized material to form each lens. The two separate elements are positioned in an overlapping arrangement, defined as an “inner” polarized element and an “outer” polarized element. The inner polarized elements for each lens are permanently attached to the frame. The outer polarized elements are positioned in a channel in the frame and held in a “rotatable” configuration such that the outer polarized elements are capable of rotating with respect to the inner polarized elements, where the angular separation between the polarization orientations of the pair of elements will dictate the degree of tint that is achieved.
In the Baran et al. arrangement, the rotation of the outer polarized elements is controlled by the manipulation of a gear wheel by the wearer. The outer elements are formed to include gear teeth around their periphery, where these teeth will mesh with the gear wheel when the various piece parts are combined. While somewhat of an improvement, the need to include teeth around the periphery of the lens elements is a time-consuming (and thus expensive) proposition. Moreover, the manipulation of the gear wheel itself may be difficult, and its position on the nose piece of the frame may be unacceptable and unnecessarily limit the types of frames within which these adjustable tint lenses may be used.
Thus, a need remains in the art for eyewear that may include an adjustable tint, where the adjustment is provided simply and easily by the wearer, without the need to incorporate difficult components and piece parts into the structure of the frame.